Large diameter, power driven sockets are commonly secured to the drive plug of the power drive tool by inserting a steel pin into aligned bores between the socket and drive plug. The socket is commonly provided with a peripheral groove intersecting the bore which receives the retaining pin and an O-ring is seated in this peripheral groove to prevent accidental dislodgement of the steel pin from the aligned bores.
Since the retaining pin and O-ring are separate elements, one or both of these elements can be lost or unavailable, and workmen frequently use the tools without these elements. Workmen using the tool with the steel pin but without the retaining O-ring have been injured when the pin has dislodged and struck them. Steel pins also can jam in the receiving bores when the drive surfaces of the drive plug or of the retaining hole in the socket become worn and misaligned.